gdb/testsuite/gdb.python/flexible-array-member.exp

# Copyright 2020-2021 Free Software Foundation, Inc.

# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

# Test getting the range of flexible array members in Python.

standard_testfile

if { [prepare_for_testing "failed to prepare" \
	${testfile} ${srcfile}] } {
    return
}

# Skip all tests if Python scripting is not enabled.
if { [skip_python_tests] } { continue }

if { ![runto break_here] } {
    untested "could not run to break_here"
    return
}

# The various cases are:
#
#  - ns: flexible array member with no size
#  - zs: flexible array member with size 0 (GNU C extension that predates the
#    standardization of the feature, but widely supported)
#  - zso: zero-size only, a corner case where the array is the sole member of
#    the structure

gdb_test "python ns = gdb.parse_and_eval('ns').dereference()"
gdb_test "python zs = gdb.parse_and_eval('zs').dereference()"
gdb_test "python zso = gdb.parse_and_eval('zso').dereference()"

# Print the whole structure.

gdb_test "python print(ns)" "{n = 3, items = $hex}"
gdb_test "python print(zs)" "{n = 3, items = $hex}"
gdb_test "python print(zso)" "{items = $hex}"

# Print all items.

gdb_test "python print(ns\['items'\])" "$hex"
gdb_test "python print(ns\['items'\]\[0\])" "101"
gdb_test "python print(ns\['items'\]\[1\])" "102"
gdb_test "python print(ns\['items'\]\[2\])" "103"

gdb_test "python print(zs\['items'\])" "$hex"
gdb_test "python print(zs\['items'\]\[0\])" "201"
gdb_test "python print(zs\['items'\]\[1\])" "202"
gdb_test "python print(zs\['items'\]\[2\])" "203"

gdb_test "python print(zso\['items'\])" "$hex"
gdb_test "python print(zso\['items'\]\[0\])" "301"
gdb_test "python print(zso\['items'\]\[1\])" "302"
gdb_test "python print(zso\['items'\]\[2\])" "303"

# Check taking the address of array elements (how PR 28675 was originally
# reported).

gdb_test "python print(ns\['items'\] == ns\['items'\]\[0\].address)" "True"
gdb_test "python print(ns\['items'\]\[0\].address + 1 == ns\['items'\]\[1\].address)" "True"
gdb_test "python print(zs\['items'\] == zs\['items'\]\[0\].address)" "True"
gdb_test "python print(zs\['items'\]\[0\].address + 1 == zs\['items'\]\[1\].address)" "True"
gdb_test "python print(zso\['items'\] == zso\['items'\]\[0\].address)" "True"
gdb_test "python print(zso\['items'\]\[0\].address + 1 == zso\['items'\]\[1\].address)" "True"

# Verify the range attribute.  It looks a bit inconsistent that the high bound
# is sometimes 0, sometimes -1.  It depends on the way the flexible array
# member is specified and on the compiler version (the debug info is
# different).  But that's what GDB produces today, so that's what we test.

gdb_test "python print(ns\['items'\].type.range())" "\\(0, 0\\)"
gdb_test "python print(zs\['items'\].type.range())" "\\(0, (0|-1)\\)"
gdb_test "python print(zso\['items'\].type.range())" "\\(0, (0|-1)\\)"

# Test the same thing, but going explicitly through the array index's range
# type.

gdb_test "python print(ns\['items'\].type.fields()\[0\].type.range())" "\\(0, 0\\)"
gdb_test "python print(zs\['items'\].type.fields()\[0\].type.range())" "\\(0, (0|-1)\\)"
gdb_test "python print(zso\['items'\].type.fields()\[0\].type.range())" "\\(0, (0|-1)\\)"